FILE - This Oct. 24, 1986 file photo of Liberal MP for Rochdale Cyril Smith. A former police officer alleges that British detectives were ordered to drop an investigation into sexual abuse allegations against the late lawmaker Cyril Smith. The new claim, aired late Monday March 16, 2015 on BBC's "Newsnight" program, adds to allegations that a toxic mix of sexual abuse, power and silence scarred the lives of British children for decades. (AP Photo/PA, File)

LONDON — A toxic mix of misuse of power and official silence has become Britain's shame as the country faces up to a growing web of evidence that the abuse of vulnerable children by powerful men was covered up for decades.

Several lawmakers said Tuesday that former detectives and intelligence officers should be guaranteed protection from prosecution if they speak out about child abuse by senior police, politicians or other prominent people.

"I would just very much hope the police now can investigate this very thoroughly without fear or favor, get to the bottom of the truth," Deputy Prime Minister Nick Clegg said after the BBC aired new claims of a cover-up of pedophile behavior three decades ago.

"I would urge anyone who has any information that can cast any light on what happened way back then to come forward and co-operate with the police."

Many Britons have felt a creeping horror over the last few years as allegations of child abuse have piled up.

There was the revelation that the late children's entertainer Jimmy Savile had abused children in hospitals, children's homes and TV studios for decades. Separately, police announced they were investigating claims of a pedophile ring involving powerful politicians. And gangs of men in several regional towns were convicted of sexually exploiting teenage girls.

The latest allegations came Monday, when the BBC's "Newsnight" program reported that an ex-detective had told it that a lawmaker, Cyril Smith, was arrested in the early 1980s as part of an investigation into child-sex parties, but was released hours later.

He said officers were ordered to hand over notebooks and video footage from their undercover operation, and were told they would be violating the Official Secrets Act if they revealed what had happened.

The BBC did not identify the former detective because of the legal threat hanging over him.

After Smith died in 2010, prosecutors revealed that in 1970 eight men had accused the Liberal lawmaker of abusing them as teens. The prosecutors said Smith was never charged, but should have been.

Labour Party lawmaker Tom Watson, who has campaigned to expose sexual abuse by politicians, said former police officers and civil servants with information have a duty to come forward, and should be protected from prosecution.

Legislator Simon Danczuk, who represents the Rochdale constituency that Smith once held, also said whistleblowers "should be given the freedom to speak out" without fear of prosecution.

A dam of official silence around child abuse in Britain began to break after the 2011 death of Savile allowed his long-silent victims to come forward.

Since then, several once-prominent entertainers, including TV host Rolf Harris and former glam rock star Gary Glitter, have been convicted and police have reopened dormant abuse inquiries.

But police have been accused of having been part of the problem by suppressing allegations against well-connected pedophiles. On Monday, Britain's independent police watchdog said it was looking into allegations that Scotland Yard covered up historic allegations of child abuse from the 1970s to the 2000s.

Several recent cases in which gangs of men have been convicted of sexually exploiting girls in the care of local authorities have also exposed failures by police and social services.

In those cases, the perpetrators were mainly of South Asian origin, and their trials heightened racial tensions in northern towns such as Rochdale and Rotherham.

But Home Secretary Theresa May, Britain's top law-and-order official, has warned that abuse revelations will touch the whole country, and all sections of society.

May has ordered a public inquiry into how public agencies — including government bodies, police, hospitals, churches and the BBC — handled child-abuse allegations.

The abuse claims reach so deeply into the upper echelons of British society that finding a figure to head the inquiry has been problematic. Two chairwomen were appointed and then rejected because of their connections to the establishment. Last month a judge from New Zealand, Lowell Goddard, was selected to lead the probe.

"We already know the trail will lead into our schools and hospitals, our churches, our youth clubs and many other institutions that should have been places of safety but instead became the setting for the most appalling abuse," May wrote in the Daily Telegraph last week.

May said that many Britons did not yet appreciate "the true scale" of past abuse.